A typical data processing system, such as a computer, microcomputer, embedded microcontroller, or other computational device, includes a central processing unit (CPU), a peripheral device interface, and a memory device. The memory device stores instructions, which are executed by the data processing system to perform a desired task. The data processing system stores and retrieves information at the memory device using an appropriate memory interface device and memory interface protocol. The memory interface protocol is often promulgated as an industry standard.
Standards are often developed and ratified by industry representatives to facilitate interoperability of device components provided by multiple manufactures. Industry standards are prevalent in the electronics industry, and cover most aspects of technology, including memory interfaces. Memory device standards can define electrical, operational, and physical attributes of a memory device so that manufacturers of individual components of a data processing system can ensure operability with memory devices provided by different memory device manufacturers.
The Joint Electron Devices Engineering Council (JEDEC) Solid State Technology Association is the semiconductor engineering standardization body of the Electronic Industries Alliance (EIA). JEDEC has set forth a memory device standard referred to as double data rate (DDR) synchronous dynamic random access memory (SDRAM) that is currently especially popular. The original DDR JEDEC standardization specification was published in the year 2000. The original DDR standard (referred to here as DDR1) was very successful and subsequent variations of the DDR standard have been adopted by industry, such as DDR2 and DDR3, which describe memory devices with increased access bandwidth and operating frequency. However, memory devices that comply with one memory standard typically cannot be substituted for devices compliant to a different memory standard.
New memory standards are revised and introduced with such regularity that the longevity of a particular standard can be relatively short. Memory suppliers are quick to transfer development and manufacturing resources to reflect a revised standard. As a result, manufacturers of equipment that interface to memory devices must regularly re-design their products to operate with memory devices that comply with the newest standard, or else stockpile inventory of memory devices that can otherwise become unavailable or prohibitively expensive.